PRESTO, Japan Science and Technology Agency, 4-1-8 Honcho, Kawaguchi, Saitama, 332-0012, Japan.
J Am Chem Soc. 2020 Dec 9;142(49):20701-20707. doi: 10.1021/jacs.0c09200. Epub 2020 Nov 23.
Raman probes based on alkyne or nitrile tags hold promise for highly multiplexed imaging. However, sensing of enzyme activities with Raman probes is difficult because few mechanisms are available to modulate the vibrational response. Here we present a general strategy to prepare activatable Raman probes that show enhanced Raman signals due to electronic preresonance (EPR) upon reaction with enzymes under physiological conditions. We identified a xanthene derivative bearing a nitrile group at position 9 (9CN-JCP) as a suitable scaffold dye, and synthesized four types of activatable Raman probes, which are targeted to different enzymes (three aminopeptidases and a glycosidase) and tuned to different vibrational frequencies by isotope editing of the nitrile group. We validated the activation of the Raman signals of these probes by the target enzymes and succeeded in simultaneous imaging of the four enzyme activities in live cells. Different cell lines showed different patterns of these enzyme activities.
基于炔烃或腈基标签的拉曼探针有望实现高度多重成像。然而，由于可用的调节振动响应的机制很少，因此用拉曼探针检测酶活性具有一定的难度。在这里，我们提出了一种通用策略，用于制备具有反应活性的拉曼探针，这些探针在生理条件下与酶反应时由于电子预共振（EPR）而显示出增强的拉曼信号。我们鉴定了一种在 9 位带有腈基的呫吨衍生物（9CN-JCP）作为合适的支架染料，并合成了四种类型的反应性拉曼探针，这些探针靶向不同的酶（三种氨肽酶和一种糖苷酶），并通过对腈基的同位素编辑来调节不同的振动频率。我们通过靶酶验证了这些探针的拉曼信号的激活，并成功地在活细胞中同时对四种酶活性进行成像。不同的细胞系显示出不同的酶活性模式。
